The present invention relates to burets with foot valves for medical infusion equipment.
Burets of the above type are generally known, for example, from the documents U.S. Pat. No. 4,175,558 (in which the foot valve includes a floating ball-type obturator) and U.S. Pat. No. 4,078,563 (in which the foot valve consists of a floating disk).
In greater detail, the invention relates to a buret of the type comprising an elongated transparent cylindrical container having a top inlet for the liquid, a bottom wall with a central hole for outlet of the liquid, a lateral graduated scale for indication of the level of the liquid inside the container, a float disk co-operating inside the container with the graduated scale for immediate identification of said level, and a valve obturator associated to the float disk for closing the outlet hole when, during use, the liquid inside the container comes to an end.
Burets of this type, which are currently manufactured and marketed by the present applicant, afford, thanks to integration between the floating indicator disk and the valve obturator, the advantage of a construction that is relatively simple, and hence more economical, as well as being of a high level of reliability and safety of operation as compared to solutions that envisage, for the floating indicator and the valve obturator, two distinct and independent elements. However, the aforesaid known burets, in which the obturator is formed by an element made of elastomeric material rigidly fixed to the float disk, are not always able to ensure proper closing of the outlet hole in the bottom wall of the container. In fact, closing is generally guaranteed when, during use, the buret is set in a perfectly vertical position, or else with just a small angle of inclination with respect to the vertical, When, instead, for any reason the inclination of the buret exceeds 10-15 degrees (in extreme cases up to 30 degrees), the float disk, which is kept horizontally on the surface of the liquid, may impinge on the inclined side wall of the buret or in any case also set itself in a more or less inclined position with respect to the bottom wall of the buret, so preventing the valve obturator from closing the outlet hole correctly when the liquid comes to an end. In the medical applications in question, the above drawback may entail even serious consequences for the patient who is connected to the buret.
The purpose of the present invention is to overcome the above drawback, and more in particular to provide a buret of the type defined above, shaped in such a way as to ensure in any operating condition, namely, even with major inclinations with respect to the vertical, correct, safe, reliable and complete closing of the foot valve when the liquid inside the container comes to an end.
According to the invention, the above purpose is achieved essentially thanks to the fact that the aforesaid valve obturator is made of a soft elastic material and is floating with respect to the float disk.
In greater detail, the float disk has a central opening through which there is inserted, with axial and radial play, a generally cylindrical body made of elastic material which has two end radial flanges facing on opposite sides said opening, one of the said flanges constituting said valve obturator.
The valve obturator and the float disk may be of equal, or more conveniently different, absolute gravity.
According to another aspect of the invention, the bottom wall of the container defines, around the aforesaid outlet hole, a sump designed to house said obturator when the float disk rests against said bottom wall.